Imaging apparatus

ABSTRACT

A machine for automatically producing images from photoelectrophoretic suspensions using a cylindrical transparent conductive electrode which is inked and contacted by an imaging electrode in the presence of an electric field and electromagnetic radiation in image configuration. The cylinder electrode is cleaned and an image transferred from its surface to a transfer material. The electromagnetic radiation is imaged at the intersection of the transparent cylindrical electrode and the imaging electrode. The projection passes from the end of the transparent cylindrical electrode to an internal mirror for reflection to the intersection.

United States Patent [72] Inventors Raymond K. Egnaczak 3,452,181 6/1969Stryzewaki 355/3 Willlamson; S I M Gino F.Squassoni Pittsiord both ofMr. [21] A 1 No 876 640 ASSISM'II Examiner-D. J. Clement [22] m" 14 1969Attorneys-James J. Ralabate, David C, Petre. and Barry a 45 PatentedSept. 28, 1971 Jay Kesselma" [73] Assignee XeroxCorporation Rochester,N.Y.

[54] IMAGING APPARATUS 15 Claims, 6 Drawing Figs.

52 us. Cl 35513, 355/8, 355/27, 355/28, 355/32, 355/47 [5 1] Int. Cl...;.J 603g 15/00 [50] Field of Search 355/3,8, 47, 4, 48, 49, 50, 17; 96/1[56] References Cited UNITED STATES PATENTS 3,485,738 12/1969 Carreira204/81 PATENTEU was m SHEET 1 [IF 4 IN VENTORS RAYMOND K.EGNACZAK GINOF. SQUASSONI ATTORNEY PATENTED SEP28l97| 3,609,028

sum 2 or 4 This invention relates to imaging machines and moreparticularly to machines employing photoelectrophoretic imagingtechniques.

Since the new invention of photoelectrophoresis was disclosed forfornring black and white or full color images, various machineembodiments have been envisioned to accommodate this i 8i 8 technique inan automated machine environment. The basic inventions are described inU.S. Pat. Nos. 3,384,488; 3,384,565; 3,384,566, and 3,383,993. Theydisclose how to produce a visual image at one or both of two electrodesbetween which photoelectrophoretic particle suspensions are placed. Theparticles are photosensitive and appear to undergo a net change incharge polarity or a polarity alteration by interaction with one of theelectrodes upon expo sure to activating electromagnetic radiation.Mixtures of two or more differently colored particles can secure variouscolors of images. Theparticles will migrate from one of the electrodesunder the influence of an electric field when struck with energy of awavelength within the spectral response of the colored particles.

A continuous imaging machine was disclosed in U.S. Pat. No. 3,427,242which depicts apparatus for forming continuous images fromphotoelectrophoretic suspensions by projection of an original utilizingsystem requiring the image light rays to pass twice through the surfaceof a transparent cylindrical electrode. A problem may arise if thetransparent cylindrical electrode is not completely cleaned of residualsuspension materials when new images are being formed since that wouldinterfere with the optical system. This problem may be severe in thenonirnage area where defects or residual materials can cause imagingdegradation and light losses at the imaging zone between the transparentand imaging electrodes.

Therefore, it is an object of this invention to improve apparatus forautomatically producing images. Another object of this invention is toemploy the photoelectrophoretic technique in an improved automatedcontinuous image-forming machine. Another object of this invention is toimprove image-maintaining members for automatically forming and carryingan image for transfer to a transfer material. Yet another object of thisinvention is to project an object to be imaged internal to a transparentcylindrical member.

These and other objects of this invention are accomplished by use of atransparent cylindrical, image-carrying, electrode member that rotatesthrough a path interfacing with a series of components utilized forautomated image formation on a support material. Photosensitive materialis supplied between an imaging electrode and the transparentimage-carrying cylindrical member in an electric field at an imagingposition where light rays are projected from an object. The object lightrays are projected from an open end of the transparent cylindricalmember to a mirror internal to the cylindrical member for reflecting thelight rays to the image plane between the two electrodes. The light raysare projected from the object as a flowing image moving in synchronismwith the surface of the transparent member where it interfaces with theimaging electrode. The transparent, image-carrying, cylindrical memberinterfaces with a transfer mechanism after a transferable image isformed at the imaging position. The member is then cleaned by suitablecleaning apparatus after which it may again coact with the imagingelectrode forming further images in the same manner as described above.

The invention herein is described and illustrated in a specificembodiment having specific components listed for carrying out thefunctions of the apparatus. Nevertheless, the invention need not bethought of as being confined to such a specific showing and should beconstrued broadly within the scope of the claims. Any and all equivalentstructures known to those skilled in the art can be substituted forspecific apparatus disclosed as long as the substituted apparatusachieves a similar function. It may be that other processes or apparatuswill he invented having similar needs to those fulfilled by the hereinto describe an invention for use in apparatus other than the embodimentshown.

These and other objects and advantages will become apparent to thoseskilled in the art after reading the following description taken inconjunction with the accompanying drawings wherein:

FIG. I schematically illustrates an embodiment of a machine for formingphotoelectrophoretic images in accordance with this invention;

FIGS. 2-4 are portions of alternative schematic embodiments for theapparatus of FIG. 1;

FIG. 5 is a side sectional representation of the projection and drivemechanism; and

FIG. 6 is a timing diagram of the machine embodiment of FIG. 1.

A detailed description of the operation and theories relating to theactual imaging system automated by this invention and discussing theinteraction of the photoelectrophoretic particles in the suspension usedfor image formation is found in the above cited patents. The imagingsystem therein described and which can be employed in the apparatusdescribed herein operates by producing electromagnetic radiation inimage configuration to which the individual photoelectrophoreticparticles within the suspension are sensitive. The activating radiationand an electric field across the imaging suspension combine between twoelectrodes in the imaging area. An electrode referred to as thetransparent injecting electrode" is maintained electrically positiverelative to "imaging electrodes interfacing with it at the imaging areaacross the photosensitive suspension. Therefore, particles within the 4suspension that are negatively charged will be attracted to therelatively positive, transparent injecting electrode.

The injecting electrode" is so named because it is thought to injectelectrical charges into activated photosensitive particles duringimaging. The term photosensitive" for the purposes of this inventionrefers to the property of a particle which, once attracted to theinjecting electrode, will alter its polarity and migrate away from theelectrode under the influence of an applied electric field when exposedto activating electromagnetic radiation. The term suspension" may bedefined as a system having solid particles dispersed in a solid, liquidor gas. Nevertheless, the suspension used in the embodiment of thisinvention described herein is of the general type having a solidsuspended in a liquid carrier. The tenn imaging electrode" is used todescribe that electrode which interfaces with the injecting electrodethrough the suspension and which once contacted by activatedphotosensitive particles will not inject sufficient charge into them tocause them to migrate from the imaging electrode surface. The imagingzone or imaging area is that zone between two electrodes wherephotoelectrophoretic imaging occurs.

The particles within the suspension are generally insulating when notstruck by activating .radiation within their spectral response curve.The negative particles come into contact with or are closely adjacent tothe injecting electrode and remain in that position under the influenceof the applied electric field until they are exposed to activatingelectromagnetic radiation. The particles near the surface of theinjecting electrode make up the potential imaging particles for thefinal image to be reproduced thereon. When activating radiation strikesthe particles, it makes them conductive "creating" an electricaljunction of charge carriers which may be considered mobile in nature.The negative charge carriers of the electrical junction orientthemselves toward the positive injecting electrode while the positivecharge carriers move toward the imaging electrode. The negative chargecarriers near the particle-electrode interface at the injectingelectrode can move across the short distance between the particle andthe surface of the electrode leaving the particle with a net positivecharge. These polarity altered, net positively charged particles are nowrepelled away from the positive surface of the injecting electrode andare attracted to the negative surface of the imaging electrode. Ac-

apparatus described and claimed herein and it is the intentioncordingly, the particles struck by activating radiation of a wavelengthwith which they are sensitive, i.e., a wavelength which will cause theformation of an electrical junction within the particles, move away fromthe injecting electrode to the imaging electrode leaving behind onlyparticles which are not exposed to sufficient electromagnetic radiationin their responsive range to undergo this change.

Consequently, if all the particles in the system are sensitive to onewavelength of light or another and the system is exposed to an imagewith that wavelength of light, a positive image will be formed on thesurface of the injecting electrode by the subtraction of bound particlesfrom its surface leaving behind particles in the unexposed areas only.The polarities on the system can be reversed and imaging will occur. Thesystem may beoperated with dispersions of particles which initially takeon a net positive charge or a net negative charge.

The imaging suspension may contain one, two, three or more differentparticles of various colors having various ranges of spectral response.In a monochromatic system the particles included in the suspension maybe of any color and produce any color and the particle spectral responseis relatively immaterial as long as there is a response in some regionof the spectrum which can be matched by a convenient radial tionexposure source. In polychromatic systems the particles may be selectedso that particles of different colors respond to necessarily listed inthe sequence that they occur) take place:

(i) migration of the particles toward the injecting electrode due to theinfluence of the field, (2) the generation of charge carriers within theparticles when struck with activating radiation, (3) particle depositionon or near the injecting electrode surface, (4) phenomena associatedwith the forming of an electrical junction between the particles and theinjecting electrode, (5) particle charge exchange with the injectingelectrode, (6) electrophoretic migration toward the imaging electrode,and (7) particle deposition on the imaging electrode. This leaves apositive image on the injecting electrode.

After the image is formed on the injecting electrode, the electrode maybe brought into interface with a transfer member which has a chargepolarity opposite to that of the imaging electrode. The injectingelectrode is now maintained negative relative to the transfer member.The particles having a net negative charge will be attracted to therelatively positive transfer member. If a support material is interposedbetween the transfer member and the particle image, the particles willbe attracted to the support material. Therefore, a photo graphicallypositive image can be fonned on any support material.

FIG. 1 illustrates schematically a machine embodiment of this inventionfor automatically forming photoelectrophoretic images. Although themachine is not restricted to the input original which is to be reimagedand copied it is preferred that a transparency input be used.

A timing diagram (FIG. 6) will describe the coordinated actions of thevarious components used in the illustrations of this invention but forthe time being the photoelectrophoretic imaging process may be describedin relation to H6. 1 by viewing the various stations positioned aroundthe injecting electrode 1. At the first station, Station A, the surfaceof the injecting electrode 1 is cleaned of any residual materials orwaste products from the previous image formations. A preclean foamroller 2 rotates in contact with the surface 3 of the injectingelectrode cylinder. it in turn is cleaned by a protruding bar 5 pinchingthe foam material of the roller 2. This action squeezes out liquids andsolid materials suspended therein to be evacuated from the immediatevicinity of the foam roller and protruding bar via a vacuum duct 7. Abaffle arm 9 aids in collecting the materials squeezed out of the foamroller 2 for removal from the system.

A wiper blade 10 contacts the surface 3 of the injecting electrode 1 totrap any liquids left on the surface 3 after in teraction with the foamcleaner roll 2. The vacuum squeegee lected materials through the vacuumduct 12. To ensure full cleaning a cleaning brush 14 contacts and driesthe surface 3 of the injecting electrode. Through suitable duct work 16this mechanism is also attached to a pressure reducing means 18 as arethe other vacuum ducts 7 and 12 of the cleaning system. Each of thethree subsystems are cyclically removable from the path of rotation ofthe injecting electrode cylinder 1. Therefore, a solenoid 8 moves thehousing in which the cleaning roller 2 is positioned and the solenoid l3removes the vacuum squeegee 11 while the solenoid 15 moves the cleaner14. The solenoids are activated during the machine cycle in the mannerdescribed in FIG. 6. A vacuum" as used herein refers to a negativepressure below atmospheric pressure but not necessarily a void. Likewisenegative pressure" refers to a partially evacuated state of less thanatmospheric pressure.

The cleaned injecting electrode surface 3 rotates in synchronism withthe projection of the original to be copied at the imaging area atStation B which interfaces with a first imaging electrode 20. Theelectrode 20 has a surface 21 thereon fonned of a blocking materialwhich apparently functions to prevent sufi'rcient charge injection intothe particles of the imaging suspension to cause them to migrate awayfrom its surface even if the particles are struck by electromagneticradiation of a wavelength to which they are sensitive. imagingsuspension is applied to the surface 21 of the imaging electrode 20 viaa suspension application means shown here to be an applicator roller 22.The suspension is carried around the surface 21, past a smoothing roller25 for passing a uniformly thin layer of suspension into contact withthe surface 3 of the injecting electrode.

While between the irrraging electrode 20 and the injecting electrode 1,the suspension and particles therein are subjected to electromagneticradiation in image configuration presented by the image projectionsystem to the area between the two electrodes. This image areaencompasses the contact portion between the two electrodes and thesuspension as well as surrounding areas where the suspension is in closeproximity to the injecting electrode surface 3. In short, it includesany area or portion of an area in which photoelectrophoretic migrationis likely to occur. The image light rays are projected to the image areavia a projection system including a mirror 24 which is positioned withinthe injecting electrode cylinder 1. Simultaneously, an electric field isapplied between the electrodes 1 and 20. This field can be between 300v. and 5,000 v. per mil, for example, but need only be within a range tocause particle migration when the particle is struck by activatingradiation. An electrical source 23 supplies the electrical potential.The dotted arrow and film strip 26 are shown to indicate a strip oftransparency film moved, during imaging, in the direction shown by thearrow at a velocity related to the velocity of the surface 3 of theinjecting electrode such that a flowing image of the data on the filmstrip 26 is projected to the image area in a synchronized movement withthe surface 3 of the injecting electrode moving therethrough.

After the object has been imaged at the image area, the injectingelectrode cylinder 1 continues its rotation. Simultaneously, the imagingelectrode 20 is removed from the interface position with the surface 3of the injecting electrode 1. This is accomplished by rotating theeccentric 28 thereby lowering the carriage 30. When the imagingelectrode 20 is lowered, a reversible motor 32 moves the tank carriage33 shuttling the electrode 20 away from the image area and bringing thesecond imaging electrode 34 near the area where its surface 36 caninterface with the injecting electrode 1 by the operation of theeccentric 28.

The function of the imaging electrode 34 is to remove background fromthe image formed at the image area during 7 interaction with the imagingelectrode 20. Therefore, carrier liquid is applied to the surface 36 tocarry away particles removed from the injecting electrode surface 3which are not desirable for forming the final image to be transferred. Acarrier applicator means such as the brush 42 applies fresh carrier 11,of which the wiper blade 10 is a part, removes the colto the surface 36of the imaging electrode 34 prior to that portion of the surfaceentering the image area. A cleaning mechanism including two squeegeeblades 43 and 44 maintained in a bracket 45 removes used carrier andresidual particles from the surface 36 so that only cleaned portions ofthe surface are brought to the image area. During the second pass of thesurface 3 of the injecting electrode into the image area for interactionwith the imaging electrode 36, the original document is again scanned ormoved to present a flowing image at the image area. This second scanpresents a precisely aligned projected image with the flowing imagepreviously presented at the image area and used to form the particleimage maintained on the surface 3. An electrical field of the same signas is presented between the electrodes 1 and is supplied between theelectrodes 1 and 34 by an electrical source 35.

During the rotation of the injecting electrode 1 between its interactionwith the imaging electrodes 20 and 34, the transfer mechanism and thepreviously described cleaning mechanisms are maintained out of contactwith the surface 3 and any particle suspension maintained thereon. Afterthe second pass of v p the surface through the imaging area, thetransfer mechanism 7 is interfaced with the surface 3 of the movinginjecting electrode cylinder 1.

In order to attract the particles from the injecting electrode cylinder1 at the transfer station, Station C, a potential from the electricalsource 51 is applied to the transfer roller 50. The potential isopposite in sign from that applied to the imaging 1 electrodes 20 and 34and approximately between 300 v. and

5,000 v. Between the transfer roller 50 and the surface 3 of theinjecting electrode is an image support material web 53 such as web ofpaper. The web is fed from a supply spool 54 and over idler rollers 56and 58 past a prewetting tank 59 where a liquid 60 similar to thecarrier liquid of the suspension is applied through an applicator roll61 to the surface of the web 53 that is contacted by the surface 3 ofthe injecting electrode cylinder. A pressure roll 64 is positioned onthe side of the web opposite from that being coated at the liquidcoating tank roll 61.

The wetted support material web passes over the surface of the transferroll 50 where the image formed on the surface 3 is transferred to thewetted surface of the web 53. The material is then fed through a fixer66 via a transport belt 68 where the image is dried. A cutter mechanism67 cuts the web into sheets. The cut sheets are then fed into a copycatch tray 68a for removal by the machine operator as he desires.

FIG. 2 shows a portion of the machine illustrated in FIG. 1. Only thatportion of the machine environment which is modified from that shown inFIG. 1 is reillustrated in FIG. 2. The functioning of the machine is inall matters the same as in FIG. 1 except where specifically pointed tobe different. In FIG. 2 the surface 3 of the injecting electrode 1 isinked directly by an extruder inker 70 which is moved into and out ofoperable interface with the surface 3 by a solenoid 72 connected throughsuitable linkage 73 to a bracket 74. This action pivots the extruder 70about a pivot point 76 for the necessary movement. A smoothing rod 78 isattached by a bracket 79 to the extruder and functions to ensure that asmooth layer of imaging suspension is allied to the surface 3 forimaging at the interface with the surface 80 of the electrode 81.

The functioning of the extruder is described in detail in copendingapplication Ser. No. 876,646 filed on Nov. 14, 1969 in the name ofRaymond Egnaczak.

The injecting electrode cylinder 1 passes with the imaging suspensionthereon to the interface with the electrode 81. An eccentric 28 raisesthe electrode carriage 82 for interface activities between the surface80 and the surface 3 of the interacting electrodes in order to fon'n animage. Image light rays are projected via mirror 24 to the interfacebetween the two electrodes for image formation.

The electrical field used for causing the migration of particles inimage configuration is supplied by a corona discharge device such as thecorotrons 84 operatively near the surface the image area. Immediatelydownstream from the image area of the machine is a corona dischargedevice corotron 86 used to discharge the surface and any suspensiongathered thereon during the imaging cycle. A scrubbing brush 88 removesthe particles from the surface 80 with the aid of a cleaning fluid 89maintained in the sump portion of the tank 82. Squeegee blades 90 and 91can be moved into and out of contact via a pivotable bracket 92 to helpwipe the surface 80 clean of fluids and particles. A sprayer nozzle 94is adapted to spray fresh cleaning fluid onto the surface while aremovable wiper blade 96 when applied prevents any fluids from passingits edge along the surface 80. During a portion of the two pass machinecycle when the transparent electrode rotates 720 or more, it ispreferable to allow carrier fluids dispensed through the sprayer 94 toremain on the surface 80 of the electrode 81 to aid in the removal ofparticles in image configuration from the surface 3 of the injectingelectrode 1. When this sequence of machine operation is desired, thewiper blade 96 can be removed from the surface 80 of the electrode 81 byactivating the solenoid 98.

FIG. 3 again illustrates the machine shown in FIG. 1 and is similar tothat shown in FIG. 2 except that the electrical field is supplied by apotential source 99 similar to the source 23 of FIG. 1. Also similar toFIG. 1, the inking is done directly on the surface 100 of the imagingelectrode here designated as 101. The ink is applied by an extruder 102and smoothed by a smoothing rod 104 so that a smooth layer of imagingsuspension is presented at the interface between the surfaces 3 and 100of the interacting electrodes. A solenoid 106 moves the ink suspensionsupplying and smoothing means into operable position with the surface100 and only in that position is imaging suspension supplied through theextruder 102. Here, as in FIG. 2, the corotrons 86 are used to dischargethe surface 100 of the imaging electrode 101. All other apparatus shownfunction in the manner described in the previous figures.

In FIGS. 2 and 3 it may be desirable to rotate the injecting electrodecylinder past the imaging electrode a second time without theapplication of ink. This obtains a function similar to that described inconjunction with electrode 34 of FIG. 1. This can be accomplished bymerely disengaging the inking mechanism 70 of FIG. 2 or 102 of FIG. 1and removing the wiper blade 96 so that fresh carrier material can bebrought to the interface from the sprayer 94 via the surface of theimaging electrode.

Another configuration is shown in FIG. 4. Once again the function isthat of the machine described in FIG. 1 and common reference numeralsrefer to common apparatus of the previous figures. The imaging electrodein FIG. 4 is composed of a conductive inner core 110 and a flexiblecontinuous belt 1 12 formed of a blocking material similar to thesurface 21 of FIG. 1. This blocking material may be any materialfunctioning in a manner described in US. Pat. No. 3,383,993 referred toabove being any suitable material having a resistivity about 10 ohm-cm.or greater. The necessary electrical field is sup plied by an electricalpower source 114 connected to the conductive core 110 of the injectingelectrode system. Imaging suspension is applied and smoothed by theextruder 102 and smoothing rod 104 in the manner described in FIG. 3.

After the flexible imaging electrode surface 112 passes the interface ofthe injecting electrode surface 3, it is transported past coronadischarge devices such as the corotrons 116 where residual charge on thesurface 112 or the suspension adhering thereto are neutralized. The beltcontinues to move into the tank 118 around a power roller 120, poweredby motor 121, and an idler roller 122. In the tank 118 cleaning brushed124 and 126 apply cleaning solution 128 to the surface 112 to removeresidual materials therefrom. Intermittent squeegee wipers 129-133 wipethe fluids from the belt 112 removing all residual fluids andcontaminants therefrom. The belt egresses from the tank 1 18 for furtherapplication of imaging suspension by the extruder 102 or for applicationof carrier liquid via the sprayer 94. If the latter occurs, the belt 80of the electrode 81 upstream from the interface position of 75 functionsin a manner similar to the surface 36 of the electrode 34 of FIG. 1.Therefore, it brings carrier solution to the interface with the surface3 for removal of background particles therefrom. The mechanism can becycled to image on one pass or on two passes as described in FIG. 1 byengaging or disengaging the image supply extruder or the fluid sprayer.

imaging suspension is pumped by pump P-! to the extruder 102 from animage suspension supply tank 136 when the imaging suspension isrequired. When no suspension is being supplied to the surface 112, thepump P-l is disengaged ending the ink supply to the belt surface 112.When the sprayer 94 is functioning to supply the belt surface 112 withcarrier fluids, the pump P-2 draws the necessary fluids from the fluidsupply sump 138. When the sprayer is not actively engaged in the imagingprocess the pump P-2 is deactivated so that no fluids are sprayed fromthe sprayer 94.

Particular benefits are derived from the use of an imaging electrodecontinuous belt that are not provided by the roller type electrodesshown in the previous figures. For example, there is more time forcleaning the surface and dissipating the residual charges maintainedthereon during the process.

FIG. is a side sectional view of a portion of the apparatus shownschematically in FIG. 1. Like reference numerals represent like parts oneach of the drawings. The injecting electrode 1 has a surface 3 of anelectrically conductive transparent coating 3 over a transparent glasssubstrate 150. The injecting electrode structure can be NESA glass whichis a tin oxide coated glass structure available from Pittsburgh PlateGlass Company. It could also be fonned by an electrically conductivetransparent coating over a transparent substrate for the purposes ofthis invention.

The entire drum 1 is mounted on an end cap 151 which is formed on ahollow shaft 152. The shaft 152 rotates from the action of the motor M-lthrough the bearing 153 in the machine frame member 154. However, themirror 24 remains stationary in its housing 155 because the shaft 156formed as part of the housing is held fast. it is unaffected by therotation of the hollow shaft 152 since it passes between bearings 157and 158 providing for movement of the hollow shaft 152 without affectingthe shaft 156.

The optical object is a film strip transparency 160 held within aprojector 161 that moves the film strip 160 in synchronized movementwith the rotation of the injecting electrode drum 1. The projection isenlarged and reflected off the mirror 24 to the inside surface of theinjecting electrode 1. Since the injecting electrode drum istransparent, the light rays 162 and 163 pass through the drum to theouter surface interface with the imaging electrode 20. The imagingelectrode has a surface 22 thereon formed of a plastic such as Tedlar, apolyvinylfluoride, made by E. l. du Pont de Nemours and Co. which haselectrical qualities desirable for the imaging process having aresistivity of at least ohm-cm. The inner structure of the imagingelectrode is an electrically conductive material 168 formed of a rubberor other resilient material having good electrical qualities. Apotential is applied to the imaging electrode 20 through an electricalconnection 169 making a field across the interface of between 300 v. and5,000 v. A similar electrical connection 170 applies an electricalpotential of opposite sign to that of the imaging electrode on thetransfer roller 50 having the web of support material 53 passingthereover. The injecting electrode drum 1 is mounted within the frame172 by a bearing 173 which cooperates in conjunction with the bearing153 to maintain the drum in a circular path during its rotation throughthe movement of the shaft 52.

The timing diagram, FIG. 6, relates to the machine shown schematicallyin FIG. 1. The vacuum equipment referred to as 18 is turned on with themachine and remains on for the entire operation of the machine. Variousmotors used to operate the various moving parts discussed can assume tobe turned on simultaneously with the required motion or activity of thepart and turned off immediately thereafter. Other apparatus would remainactivated for as long as the machine is in a ready position. Thecleaning brushes of section A namely 2 and 14 are rotated when themachine is turned on and the solenoids 8 and 15. Shortly afier theactivation of the cleaning mechanisms and the solenoids 8 and 15, thesolenoid 13 moves the vacuum squeegee 11 so that the blade 10 contactsthe surface 3 of the injecting electrode 1.

Next, the applicator roll 22 begins to apply imaging suspension to thesurface 21 of the first imaging electrode 20. After ink has been appliedto a portion of the surface of the imaging electrode the imagingelectrode 20 is moved into interface relation with the surface 3 of theinjecting electrode by turning the eccentric 28 via an air cylinder orsolenoid or other device. Shortly thereafter, the high voltage isactivated to cause a field between the first imaging electrode 20 andthe injecting electrode 1. The illumination system is then turned on sothat images can be projected to the image area. After imaging iscomplete, the reversible motor 32 moves the carriage 33 to its secondposition where the second imaging roller 34 is engaged at the image areawith the injecting electrode 1. Shortly thereafter, the high voltage isturned on relative to the second imaging electrode to create the fieldat the interface between it and the injecting electrode 1. While thesecond imaging pass continues the transfer roll is clutched in androtates in engagement with the injecting electrode 1 under suitablefield conditions.

As the injecting electrode transfers the image it continues its rotationthrough a third cycle where its surface is cleaned of residual materialsthereon.

While this invention has been described with reference to the structuresdisclosed herein and while certain theories have been expressed, it isnot confined to the details set forth; and this application is intendedto cover such modifications or changes as may come within the purposesof the improvements and scope of the following claims.

What is claimed is:

1. Apparatus for forming images including:

a hollow transparent member formed as a cylinder and adapted forrotating movement about a central axis,

an optical system including an illumination source and means forprojecting light to the transparent member outer surface at an imagezone, reflection means internal to said hollow transparent member suchthat the optical path passes internally through the transparent memberto the outer surface thereof,

an electrode member positioned in the path of rotation of thetransparent member for interfacing therewith at the image zone andadapted for synchronized movement with the surface of said transparentmember. and

means to couple at least one of said members to an electrical sourcecapable of forming an electric field between said members.

2. The apparatus of claim 1 including suspension application means toapply photoelectrophoretic suspension to one of said members along thepath of movement thereof prior to the interfacing therebetween.

3. The apparatus of claim 1 wherein said transparent member hasoperatively associated therewith cleaning means located in the path ofrotation of the transparent member and removably positionable to contactthe outer surface thereof.

4. The apparatus of claim 3 including image transfer means capable ofremoving suspension from the transparent member and removablypositionable to interface with the transparent member along the path oftravel thereof downstream from said electrode member.

5. The apparatus of claim 4 further including feed means for presentinga support material between said transparent member and said imagetransfer means such that the image is transferred to the supportmaterial.

6. The apparatus of claim 5 wherein said support material includes a webwherein said web is cut after transfer of the image thereto.

7. The apparatus of claim 3 wherein said suspension application meansincludes an extruder.

- 8. The apparatus of claim 7 further including a smoothing meansupstream from the extruder along the path of movement of the member.

9. The apparatus of claim 3 including means to remove said suspensionapplication means from the member with which it interacts.

10. The apparatus of claim 1 wherein said optical system includes a lensmeans having an object plane and an image plane and wherein saidtransparent member outer surface passes through the image plane at theimage zone.

11. The apparatus of claim 1 including electrode member cleaning meanspositioned in the path of travel of said electrode member.

12. The apparatus of claim 1 including means for applying electricalcharge to the surface of said electrode member.

13. The apparatus of claim 1 wherein said electrode member comprises anendless belt.

14. The apparatus of claim 1 including means to spray fluids on thesurface of the electrode member upstream from the interface of saidmember with said transparent member.

15. The apparatus of claim 1 wherein said optical projection systemincludes a movable object and image plane for presenting a flowing imageof the object at the image plane moving at the same rate as saidtransparent member surface thereat.

2. The apparatus of claim 1 including suspension application means toapply photoelectrophoretic suspension to one of said members along thepath of movement thereof prior to the interfacing therebetween.
 3. Theapparatus of claim 1 wherein said transparent member has operativelyassociated therewith cleaning means located in the path of rotation ofthe transparent member and removably positionable to contact the outersurface thereof.
 4. The apparatus of claim 3 including image transfermeans capable of removing suspension from the transparent member andremovably positionable to interface with the transparent member alongthe path of travel thereof downstream from said electrode member.
 5. Theapparatus of claim 4 further including feed means for presenting asupport material between said transparent member and said image transfermeans such that the image is transferred to the support material.
 6. Theapparatus of claim 5 wherein said support material includes a webwherein said web is cut after transfer of the image thereto.
 7. Theapparatus of claim 3 wherein said suspension application means includesan extruder.
 8. The apparatus of claim 7 further including a smoothingmeans upstream from the extruder along the path of movement of themember.
 9. The apparatus of claim 3 including means to remove saidsuspension application means from the member with which it interacts.10. The apparatus of claim 1 wherein said optical system includes a lensmeans having an object plane and an image plane and wherein saidtransparent member outer surface passes through the image plane at theimage zone.
 11. The apparatus of clAim 1 including electrode membercleaning means positioned in the path of travel of said electrodemember.
 12. The apparatus of claim 1 including means for applyingelectrical charge to the surface of said electrode member.
 13. Theapparatus of claim 1 wherein said electrode member comprises an endlessbelt.
 14. The apparatus of claim 1 including means to spray fluids onthe surface of the electrode member upstream from the interface of saidmember with said transparent member.
 15. The apparatus of claim 1wherein said optical projection system includes a movable object andimage plane for presenting a flowing image of the object at the imageplane moving at the same rate as said transparent member surfacethereat.